Using nature’s motors to deliver drugs

Bacteria and sperm have natural advantages over synthetic nanomotors when navigating the body’s byways. Image courtesy of Pixabay.com

By XiaoZhi LimChemical & Engineering News

Finding ways to deliver drugs to specific, hard-to-reach areas of the human body remains a major challenge in drug development. Drug molecules that enter the body via a pill or an injection circulate in the blood until they reach the target location—a process that can be slow and imprecise.

For years, many chemists have been building synthetic nanomotors—nanoparticles that propel themselves—to navigate the vessel-based highways of the body and drop off drugs in specific locations. But these artificial motors typically need fuels like hydrogen peroxide or glucose to run. “The motors that we can build synthetically are vastly inferior to the biological ones,” like bacterial cells or sperm that have built-in mechanisms to help them swim, says Adam W. Feinberg of Carnegie Mellon University. They’ve been optimized over millions of years and move with minimal energy consumption, he adds. So researchers are now looking to these natural motors to help do the job of drug delivery more effectively.

Bacteria, with the help of whiplike structures called flagella, swim efficiently in their environments. Escherichia coli, for example, swim at a consistent rate of 20 to 30 µm per second. Cells like E. coli and sperm can sense and respond to environmental conditions, so they could make a beeline for their target once within range. They could also help minimize the exposure of healthy tissues to drugs—and therefore reduce side effects—by releasing their cargo only after arrival. Recently, several studies have demonstrated a range of viable cargo-carrying swimmers, and researchers are optimistic that these swimming cells could enable a simple yet versatile platform for targeted drug delivery.

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If XiaoZhi is too difficult for you to say, just call me X. I am a freelance science reporter currently based in Massachusetts. I enjoy covering energy, climate, environment and basic science. I'm originally from Singapore.

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